Electrical cooking appliance



April 16, 1940. C B NELSON 2,197,056

ELECTRICAL COOKING APPLIANCE 4 Filed Sept- 22. 1938 i 2 sheets-sheet 1#a l a2 if 7 O 70 "'X f 5" f /z a ZZY 56 @z ma FI .1 ,03 A /6 ze 1' /07v /9 fo@y 0f? 50 f@ /7 awww 2,

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ATTORNEY.

April 16, 1940. c. B. NELsoN 2,197,056

ELECTRICAL COOKING APPLIANCE Filed Sept. 22, 1938 2 Sheets-Sheet 2INVENTO R C hr/.sf B. Nelson A ORNEx'.

Patented Apr. 16, 1940 UNITED STATES PATENT OFFICE Claims.

'I'his invention relates to electrically heated cooking appliances, andmore particularly to the improved arrangement of the heating means forsuch appliances.

Electrically heated cooking appliances, such as waiiie irons and thelike, have commonly used ribbon type resistance wire as a heatingelement but the wire has been disposed in the appliance so that theheating means could not be assembled or replaced as an independent unit.Additionally, the heating means in prior appliances of this type withwhich I am familiar, have not confined the heating area to an eilicientzone but considerable heat energy ls devoted to heating parts of theappliance or is radiated without contributing in any appreciable degreeto heating the material to be cooked.

The aforementioned disadvantages result in a relatively expensiveappliance not only from the standpoint of assembly and manufacture butin replacement of the heating unit and operating costs. I have providedan improved cooking appliance of this type wherein the heating means maybe inserted or replaced as a unit and wherein 85 the heating is largelyconfined to a desired area.

It is a primary object of my invention to provide an electrically heatedcooking appliance having approved heating means associated therewith.

Another object of my invention is to provide an electrically heatedcooking appliance wherein the heating means may be eiciently assembledas an independent unit and easily mounted in the appliance.

Another object of my' invention is to provide electrically heatedcooking appliances having improved heating means associated therewithand so disposed as to substantially confine the heating effect to anefilcient zone. v

Another object of my invention is to provide an improved method ofmounting resistance wire in a heating unit for cooking appliances andthe like.

Another object of my invention is to provide an electrically heatedcooking appliance wherein the heating means may be easily replaced.

Other objects of my invention and the invention itself will becomeincreasingly apparent from a consideration of the following descriptionand drawings wherein:

Fig. 1 is an elevational view mainly in sectio of a preferred form of my`invention;`

Fig. 2 is an elevational view, partiallyA diagrammatic, of a pairofheating units which I vmay employ with the deviceof Fig.,1;

(Cl. 21S- 19) Fig. 3 is a plan view of the lower heating unit of Fig. 2;

Fig. 4 is a plan view of the upper heating unit of Fig. 2;

Fig. 5 is a fragmentary perspective view of the 5 hinge connectionillustrated in Fig. 1;

Fig. 6 is an enlarged fragmentary sectional view of contacts which I mayemploy, and

Fig. 7 is a fragmentary perspective view of the heating unit housing.

Referring now to the drawings, I have illustrated an electrically heatedcooking appliance, particularly adapted to the making of waiiles and`comprising a base II and a cooperating cover generally indicated at I2.The base I I comprises l5 a sheet metal housing including a generallysquare lower portion I3 provided with a depending flange I 4 and anupstanding cylindrical portion I5, the housing being preferablyexternally plated with suitable material, such as nickel or chromium.Supported on the housing cylindrical portion I5 is a generally circularwaffle iron I6 provided with an upstanding rib I1 extending along adiameter and a similar rib I8 also extending along a diameter at rightangles to rib Il, thereby dividing the iron into quadrants. Eachquadrant is provided with a plurality of upstanding projections IShaving recesses 20 therebetween, adapted to receive similar projectionsI9 mounted on a cooperating upper similarly formed waffle iron I6. 80When the cover I2 is closed the projections vI9 on each wallie iron I6are maintained spaced from the cooperating recesses 20 so that thewaffle material may flow therebetween in a well known manner. Thespecific form of the wallie iron constitutes no essential part of myinvention and any desired form may be employed. l

The waffle iron is provided with a peripheral flange 2| adapted to seatupon the upper endof cylindrical housing portion I5. The bottom plate 4oof the base of the wallie iron I6 is provided with a centrally disposedthreaded recess to receive a stud lbolt 22, they lower end of the bolt22 being adapted to project through a central perforation provided inthe generally square plate 23 of the 45 base II, disposed within thelower portion I3 of the housing and secured by anut 24 threadedlyengaging the stud. Legs 25 are provided adjacent each corner of plate 23for supporting the appliance. Y f

A generally circular heating unit 26 is `disposed beneath the lowerwallie iron I6 and comprises a sheet metal housing element 2l includinga base 28, a peripheral upstanding annular flange 29 and radiallyinnerupstanding annular anget. 65

A relatively large central opening is thus formed in the base of element21. Theflanges 29 and 38 are slotted as indicated at 3l and 32 toprovide a plurality of pairs of vertical slots in radial alignment. Thebase 28 of element 2l is also slotted as indicated at 33, each of theslots 33 being in radial alignment with a pair of slots 3l and 32. Theseslots 3l, 32 and 33 cooperate to support insulating elements 34 formedof mica or the like. The 'insulating elements 34 each comprise an arm 35adapted to be received in slot 3I, an arm 36 adapted to be received inslot 32, and a depending arm 31 adapted to be projected through slot 33in the base of element 21. The depending arm 31 is of a length slightlyless than slot 33 so that it may be easily projected therethrough and iscut back adjacent each end, as indicated at 38 and 39, for a purpose tobe described. The upper portion of element 34 is provided with aplurality of spaced notches 4D, each notch having an inclined face 4Iterminating in an arcuate undercut portion 42.

A circular plate 46 is provided with a plurality of notches 41, each ofsaid notches having an inclined camming face 48 for a purpose to bedescribed. The notches 41 are positioned so that when the plate 46 isrotated to dispose the notches 41 in alignment with the slots 33 in thebase of element 21, the slots 33 will be entirely uncovered and as theplate is rotated out 0i alignment, the slots 33 will be partiallycovered.

The manner of quickly and easily mounting the insulating elements 34 inelement 21 will now be described:

Y"Ihe plate 46 is rotated so that the slots 41 are in alignment with theslots 33 of element 21 and the insulating elements 34 are then disposedwith arms 35 disposed in slot 3 I, arms 38 disposed in slots 32, andarms 31 projected through slots 33. Upon rotating the plate 46 in aclock-wise direction, as viewed in Fig. 4, the inclined or camming lace48 of the slot 41 will engage the cut-back portion 38 of element 34 andforce the elements 34 radially outwardly and upon continued rotation ofplate 46 to the position illustrated in Fig. 4, the un-notchedperipheral portion of plate 46 will be seated within cut-back portions38 of elements 34 and the cut-back portions 39 of elements 34 willengage the base of element 21, thereby concurrently locking all of theinsulating elements 34 in position. The base 28 of element 21 isperforated preferably at two points and the plate 46 is similarlyperforated, whereby upon plate 46 being rotated to the positionillustrated in Fig. 4, the perforations will be aligned and eyelet formrivets 45 may interlock plate 46 with element 21.

Preferably ribbon type resistance wire 58 is then wound in spiral formand secured at spaced points within the notches of insulating element34, the shape of the notches 40 permitting the wire 50 to be easilylocated within the notches and as the Wire is drawn taut, it will slidedown the inclined faces 4I of the notches and seat within the arcuateunder-cut portions 42. The aforementioned construction of the heatingunit permits the insulating elements 34 and the resistance wire to bequickly and easily assembled to provide a compact unit.

A portion of base 28 of element 21 is provided with a generallytriangular perforation 55, best illustrated in Fig. 3, disposedintermediate two adjacent insulating elements 34, and a generallytriangular mica or the like insulating strip 56is secured on the upperside of base 28 of element 21 vgaging the prongs.

and perforated whereby the ends 0i the resistance wire may be projectedtherethrough as indicated at 51 and 58. The opposite or bottom face olbase 28 of element 21 has a second strip of insulating material 59,disposed thereagainst, the strips 56 and 59 being secured by rivets 68projected throughl the strips and base 28, the rivets preferably beingof eyelet form. Strip 59 has a generally square portion extendingoutwardly beyond the periphery of base 28 and a third strip ofinsulating material 6I is secured thereto by a pair of nut and boltconnections 62. The ends of the resistance wire 50 are looped throughgrooves 63 formed in insulating strip 6I with each end of the wire beingsecured to a different nut and bolt connection 62 thereby forming aterminal connection, the connection preferably being effected byproviding a shoulder on the bolt and telescoping a washer 64 over thebolt and against the shoulder whereby the ends of wire 58 may be tightlyclamped intermediate the Washer 64 and strip 6I.

The heating units 26 are similar in construction and an insulated wire65, as best illustrated in Fig. 2, connects one of the terminals 62 ofthe lower heating unit with a terminal 62 oi' the upper heating unit. I

To secure the heating unit to the wafile iron, a stud 10 is threadedinto the wallie iron base and projected through plate 46 of the heatingunit and secured by a nut 1|.

The cover I2 comprises a housing 80 generally of inverted cup form andpreferably centrally perforated to receive a cup element 8| having thestud 22 projected through the base thereof and secured by nut 24. Athermally responsive indicating unit 82 may be mounted in the cupelement 8| after assembly of the heating unit within the housing 80. Themanner of connecting the heating unit to the power source will now bedescribed:

One of the terminals 62, as best illustrated in Fig. 2, is connected byan insulated wire 85 to one prong 86 of a plug generally indicated at 81whereby current may pass through prong 86 from the power source and bywire 85 to one terminal 62 of the lower heating unit and then throughthe resistance wire 50 and by wire 65 to the upper heating unit. Afterpassing through wire 5I) of the upper heating unit, the current passesby a wire 88 to a second prong 89 of the plug. The prongs 89 and 86 eachcomprise a pin threaded at one end and having an intermediate shoulder,preferably of hexagonal form as indicated at 98. The upstandingcylindrical portion I5 of the base housing I3 is provided with agenerally rectangular perforation at a convenient point to receive aunit comprising mica or the like washers telescoped over prongs 86 and89 and abutting the shoulders 98 formed thereon. Washers 9I are seatedwithin dished portions 92 of a generally rectangular strip 93 perforatedto receive prongs 86 and 89. A second pair of mica or the like washers94 abut the inner face of strip 93 and the washers and prongs aresecured by washers 95 and nuts 96 threadedly en- A second pair ofwashers and nuts 91 secure the ends of wires 85 and 88 to the prongswhich, in the manner described, are insulated from the cylindrical wallI5.

The strip 93 and the assembled prongs are secured to the housing wallI5-by providing lateral notches in strip 93 and bending ears 96 toengage the notches. Thus the heating units can be assembled asillustrated in Fig. 2 and quickly inose mounted within the base andcover 'of the appliance. 4

The manner of hingingly interconnecting the bottom or base II and coverQI2 will now be described:

Referring to Figs. 1 and 5, a generally U-iorm bracket |00 comprises ahorizontally extending web IOI, and spaced upstanding leg |02, thebracket being secured to the cylindrical wall I0 by projecting lugsformed on the bracket legs |02 through perforations provided therefor inthe wall I0 and bending over the lug to tightly clamp the bracket to thewall. The legs |02 are provided with elongated vertical extending slots|00. Secured in a similar manner tothe lateral wall of the cover housing00 is a second bracket of inverted U-form comprising a top |00 andintegrally formed depending arms |01, the arms each having a pin |00projected therethrough to engage the slots |03 and hingingly connectbase and cover I2. To limit opening movement of the cover I2, the legs|02 are preferably provided with laterally outwardly extending ears |00adapted to engage the bottom edge of arms |01 after the top portion I2has been opened to a substantially vertical position.

A suitable handle I I0 preferably heat insulated. is provided forlifting the cover I2 and suitable handles may be provided for liftingthe appliance bodily by clamping elements formed of heat insulatingmaterial to opposite edges of the lower portion I2 of the housing I0.

It will now be understood that I have provided heating units for thecover and base which may be quickly and easily assembled therewith andwhich confine the heating zone to the waifle iron in an eillcient mannerwithout unduly heating other parts of the appliance.

Although I have shown and described a preferred form of my invention, Icontemplate that numerous and extensive departures may be made therefromwithout departing from the spirit of my invention and the scope of theappended claims.

Having thus described my invention, what I claim is:

l. In an electrical cooking appliance, a heat retaining element adaptedto receive material to be cooked, and a heating unit therefor, said unitcomprising a housing secured to the heat retaining element, said housingcomprising a base and a pair of upstanding flanges, said base beingprovided with slots aligned withslots provided in each of said flanges,a plurality of up-standing and radially disposed insulating stripsadapted to be seated in each of said aligned slots in the housing, theportion of said strips which is projected through the slots base of saidhousing being of a length slightly less than the slot in the base ofsaid housing and being cut back adjacent each end thereof, the cut backportion of said strips being adapted to have camming engagement with theslots provided in said base whereby upon rotation of the base theinsulating strips will be forced radially outwardly to lock the same inposition, a plurality of notches in the upper portion of each striphaving an inclined face and an under-cut face portion, a flexiblecontinuous heating element seated in the notches and retained by theundercut portion, means for connecting the heating element with a sourceof power.

2. In an electrical cooking appliance, a heat retaining element adaptedto receive material to be cooked, and a heating unit therefor, said unitcomprising a generally cup-form housing secured to the bottom of theheat retaining element, said housing comprising a base and a pair ofupstanding i'langes. said base being provided with slots aligned withslots provided in each oi' said anges, a plurality of upstanding andradially disposed insulating strips in the housing, each strip having aportion seated in a slot provided in each of the housing flanges, and anotch portion projected through the aligned slot in the housing base, amovable element adapted to have camming engagement with the notchportion of each strip to retain the strip in the housing, a plurality ofnotches in the upper portion of each strip including an undercutportion, a ilexible continuous heating element seated in the notches andretained therein by the undercut portions.

3. In an electrical cooking appliance, a heat retaining element adaptedto` receive material to be cooked, and a heating unit therefor, saidunit comprising a generally cup-form housing secured to the bottom ofthe heat retaining element and having a continuous upstanding flangespaced inwardly upon the housing lateral walls, the housing lateralwalls, flange, and base being perforated to provide a series of alignedslots. a plurality of upstanding insulated strips having one end portionseated in a slot in the wall and the opposite end portion seated in aslot in the flange, the bottom portion of the strip being looselyprojected through the housing base, rotatable means engaging the bottomportion of each strip to lockingly retain the strips in position, a wireform heating element supported strips.

4. A heating unit, adapted to be secured to a grid or the like in anelectrical cooking appliance, a unit comprising a cup-form housinghaving a radially inwardly annular ange, a plurality of pairs of slots,one in the flange and the other in the lateral wall of the housing inradial alignment, a plurality of slots in the housing base intermediateeach pair of slots and in radial alignment therewith, a plurality offnsulating'strips, each strip having an end portion seated in a pair ofslots and a depending portion projected through the slot in the housingbase, the depending portion being notched at each end thereof, a movablelocking element having a plurality of slots provided in its outerperiphery, said slots each having a camming face, one of said notchesreceiving a portion of the housing base and the other notch in each ofsaid strips receiving said camming face of said movable locking elementand the upper portion of the strip being notched at spaced points, and aheating wire disposed in general spiral form seated within said upperportion notches.

5. A heating unit adapted to be secured to a grid or'the like in anelectrical cooking appliance, a unit comprising a cup-form housinghaving a radially inwardly annular flange, a plurality of pairs ofslots, one in the flange and the other in the lateral wall of thehousing in radial alignment, a plurality of slots in the housing baseintermediate each pair of slots and in radial alignment therewith, aplurality of -insulating strips, each strip having an end portion seatedin a pair of slots and a depending portion projected through the slotsin the housing base, the depending portion being notched at each endthereof, one of said notches receiving a portion of the housing base andthe other notch receiving a movable locking element and the upperportion of the strip being notched at spaced points, a. heating wiredisposed in general spiral base, and each of said slots in said lockingelement having an inclined cumming face adapted to engage a strip andi'orce the strip rdislly outwardly permitting an unnotched peripheralportion o! the plate to seat within s. notch in the 5 strip.

A(IHRIBI B. NELSON.

